I'm not sure the pros and cons of neutering as I don't own a pet yet but I feel sorry for any male creature that gets their balls removed.
I personally wouldn't like to be neutered so don't think it's a lot of fun for dogs either.
Maybe it will extend his life or reduce the chance of some diseases or give him a better temperament. I must look into this further. For now he looks a bit sad but I'm sure he'll be back to himself soon.
I know that it reduces the chance of unwanted puppies being mistreated so that itself is a good thing but a part of a dog's manhood is gone forever.